The Other Woman
by niallbranson
Summary: After an argument with Mary Morstan, Sherlock decides to prove her wrong and show her that he is more than capable of convincing a woman to be his date to Mary and John's wedding.
1. Chapter 1

My very first time publishing here. Obviously, I own nothing and everything belongs to Moffat, the BBC, and Sir ACD. I'm just playing around...

* * *

It began with Mary Morstan. Doctor Mary Morstan who headed the psychiatric department at St. Barts. Mary Morstan who had waltzed into 221B, with her designer clothes, and requested help finding her father. She'd not asked Sherlock to find him for her; she'd simply asked for his assistance. Even then, before John had made the very John-like decision of falling in "love" with her, Sherlock could tell Mary Morstan was different.

He could tell by the way she met Sherlock quip for quip, having an answer on the tip of her tongue almost before Sherlock had even finished speaking. He could tell by the way she sat up straight, poised and dignified and so very different from the ones before her; those dull and simple girls. Mary Morstan was not one of them; she was a woman. A clever and interesting woman.

It was all these things that made Sherlock sit back in his arm chair, fingers to his laptop keyboard, and a smirk on his face as Dr. Morstan sauntered around the flat, expensive heels clicking on the wooden floors, quietly observing the small things anyone else would have overlooked.

"You've moved in quite a few new things." She stated, looking around at the boxes Sherlock had hauled up a few days before. Amongst all the regular clutter of the flat, not even John had noticed the new additions. Sherlock quirked an eyebrow but didn't look up from his laptop.

"Mrs. Hudson had removed some of my things from the flat while I was dead. Put them in storage."

Mary chuckled. "It's not every day you hear someone say the _were _dead. Anyway you've been back for a while now. And you've only just found the need for your...skull?" She asked, peeking into one of the boxes where a human skull was sitting on top.

"I didn't have the time before."

"Or you've just now anticipated that you'll soon have a few new shelves available to your disposal."

Sherlock stopped typing for only a second but it was enough to let the psychiatrist know she was right.

"How odd that these new things appeared on the week John and I told you we've found a flat."

"Yes, well, seeing that I won't have a flatmate soon, I figure I could go back to talking to my skull. As much as Mrs. Hudson doesn't like it."

Mary tutted and sat on the coffee table in front of him.

"John will always be around when you need him, Sherlock." She sighed and gave him a small smile. "I'm willing to bet he'll spend more time here than at our place anyway."

Sherlock met her icy blue eyes with some added cynicism in his own.

"Really Dr. Morstan, when I find myself in need of a therapy session, I'll call you."

For all of her intelligence, Mary was, after all, a psychiatrist. She had this unshakable need to comfort and care for people and while her perceptiveness of others sometimes impressed even Sherlock, he was often let down by her ability to _care _so much. He'd once told her she could be brilliant if she removed all of the unnecessary emotions that cluttered up her mind.

"Brilliance is overrated." She had simply answered, with a small smirk on her lips and Sherlock had narrowed his eyes at her, not fully convinced there wasn't an alternate meaning to her answer.

"I wasn't trying to comfort you. I was just stating a fact. I'm afraid I've come to terms with the fact that I will come in second to you, Sherlock Holmes. Even to my own husband."

"Oh settle down Mary, he's not your husband yet!"

Brilliant as she might be, Sherlock had yet to completely forgive her for coming between him and his colleague. Alright, friend. John Watson was his friend; his best friend. One of the only meaningful relationships he had in his life was about to be taken from him and he couldn't help but resent the fact that he had been powerless to stop it.

Oh he'd tried.

He'd told John about the way she dressed: designers and labels too sophisticated for a woman to learn overnight once she makes a decent wage as a psychiatrist. No. Her fine taste was not taught; it was engrained from childhood. She came from money; and quite a lot of it. He'd told John about the lack of successful relationships in her life: not because men didn't want her, but because men _bored _her and she found them disposable. Much to John's annoyance, Sherlock had remarked that if anyone could bore Mary out of her skull it would certainly be John Watson. Much to Sherlock's own annoyance, he'd been wrong.

Most importantly however, he'd reminded John of the first thing he'd noticed about Mary Morstan: the fact that she had an almost sociopathic ability to manipulate those around her, and her being a psychiatrist was mostly a matter of chance. She could have just as easily been a hit-woman or a spy.

If he were being honest, Sherlock found it refreshing to be kept on his toes by someone; to not be able to anticipate or understand someone's motivations every single time. She would never be able to best him of course, but it was amusing to see her try. She was a bit like The Woman, but much more interested in John Watson and a lot less interested in playing games she didn't know the rules of. No, perhaps Mary was not like The Woman. Mary was not foolish; she never did anything unless she was absolutely certain of the outcome.

It was with that thought that Sherlock realized he should have been more wary of the conversation that followed that night, as Mary perched on his coffee table while he typed away a new blog entry.

"Have you thought of the wedding?" She asked him.

Without missing a beat, he responded, "It's _your _wedding Mary, I don't see why I should concern myself with it."

"Of course not. But John and I were wondering if you'd be attending alone." Sherlock was about to respond, when she added, "Well, John was wondering really."

Sherlock narrowed his eyes. "But you weren't. Either because you have a ridiculous romantic notion that I'll suddenly develop the urge to ask someone or because you're hoping I'll go alone, and you'll sit me next to your perpetually single cousin, Hattie. Don't bother, Mary, she's not interested in men." He settled back into his armchair with a smirk, satisfied for only a moment before he realized that Mary wore an unfazed expression.

"Actually," she began slowly, as if she were talking to a child. Her _therapist _voice, to be sure. "I was only not curious because I knew you would go alone."

"Oh did you?" Sherlock countered. It wasn't an awfully brilliant assumption to make, given his lack of dating history, but it bothered Sherlock to give Mary the impression that she had him figured out; which she most certainly didn't.

"Well, it's not exactly as if you know many women. Especially any that would accept going to a wedding with you. I imagine it'll be a fun-filled evening of you complaining over the farce that is marriage and the amount of money spent on such a spectacle."

"Oh, you know me so well, Dr. Morstan." Sherlock replied sourly. "You think I'm not capable of behaving, what you psychiatrists deem, "normally" and interacting with a woman for one night. I know _how _to do it: you show up, you lie through your teeth and give a compliment about her hair or the over-the-top dress she's wearing, you comment on the guests, the dinner, the _happy couple. _Just because I chose not to fill my time with something as trivial as _dating _doesn't mean the notions are lost on me."

"Of course they're not." Mary gave him another smile that went with her _therapist voice. _"But then, theory and practice are two different things."

Sherlock opened his mouth give a witty retort but was interrupted when the door to the living room flung open.

"Sorry I took so long, darling. Ready to go?"

Mary lifted herself from the table, designer purse in hand, and made her way over to where John stood.

"Of course I am. Are you sure you won't come to dinner with us, Sherlock?" She asked and Sherlock only rolled his eyes and continued typing, staying silent through John's goodbye and only looking up when he heard the front door slam shut.

"I wish you wouldn't push his buttons like that." John told his fiancé when she told him of her exchange with his best friend. "Sherlock can be hurtful when he's challenged."

"Oh I know not to take his insults to heart. But he needs a push; he needs to go out and find someone for himself; build meaningful relationships with other people. And not just you; because you, Doctor Watson, are mine." Mary tugged playfully at John's hand to bring him closer and pecked him on the cheek.

"And you think he'll go for it?"

"Oh, a little old fashioned reverse psychology never fails. Especially with someone who acts like a petulant 9 year old, like Sherlock does. I just can't possibly imagine what poor soul he's going to pick to prove me wrong. Exactly how many women does Sherlock know?"

"Women that don't want to punch him in the face?...not many." John said grimly. It would _not _be an easy task for Sherlock to prove to Mary that he was capable of acquiring a date to their wedding, there weren't exactly too many women all that eager or brave to take on Sherlock Holmes. Well, John thought suddenly, there was _one..._

A few blocks away, St. Bart's head of pathology was locking up the lab. She tugged her cherry-covered cardigan on and buttoned it wrong but she hardly cared; it had been a long day and all she wanted to do was get home, feed Toby and climb into bed.

She had just waved goodbye to the security guard, Jeff, and walked towards the hospital's main exit when her cellphone beeped and she found herself standing in the middle of the revolving door, staring down at the text on her screen in confusion.

Molly, coffee tomorrow? -SH


	2. Chapter 2

I am so, so flattered at the amazing response and reviews I got from the first part of this story. It was so encouraging and wonderful to read; especially since I've never published on here. I'm glad you're all liking the story and above all, Mary Morstan. I always pictured her so differently than what I read in fanfiction (usually Molly's chipper friend) and to me, in order for her to have a functional, interesting relationship with someone like John Watson she would have to be a lot like the only other person John has a functional relationship with: Sherlock. Although the story is most definitely Sherlolly, Mary is going to play a very central part and she is, in fact, "the other woman" from the title. I'm glad you like her so far because she'll be making many more appearances. Do leave your comments, thoughts, suggestions, anything, I love to read them! As always, everything belongs to Moffatt, ACD & the BBC. I own nothing except a lot of tears over Benedict Cumberbatch.

* * *

Sherlock Holmes prided himself in tidiness. Certainly not of 221B; he had John and Mrs. Hudson for that. But his mind palace was different. He took great pride in the fact that his mind was free of any clutter, any useless information about pop culture or relationships or whatever other rubbish people kept in there. He noticed everything, and then immediately disposed of the information he no longer found useful. He didn't remember what shows Mrs. Hudson watched on the telly or the names of the women John dated before Mary, he didn't remember Mycroft's birthday or how Lestrade took his tea.

It came with great irritation, therefore, that Molly Hooper was different. I was with an infinite annoyance that he had to dedicate a small corner of his mind palace to the shade of lipstick the pathologist wore, and how she styled her hair. At first it was painfully conscious, he had to dig around in his mind to remember what she had worn the last time they'd seen each other, come up with a way to compliment her, throw in a smile that would persuade her to let him examine a corpse, or take home body parts for his various experiments.

Soon though, it became a habit to notice all the small details about her, just in case he needed to reference them, he figured, should he ever need a favor.

And so the small place (a cupboard really, as far as he was concerned) that he had dedicated to Dr. Molly Hooper slowly started growing. The books she read and the films she liked and how she preferred coffee over tea- and subsequently, _how _she took her coffee- started crowding the tiny cupboard in his mind until he found himself with no choice but to move Molly Hooper into a _room_ of his mind palace.

He hated the idea that his space was being occupied by such silly and trivial things as to which side Molly parted her hair, what she ate for breakfast or that horrendously dull story about her molars.

It wasn't all just plain and obvious facts that Sherlock kept stored in Molly's space inside his mind. There were other things; things he observed which were far more interesting than the things she said or the things that were merely on the surface. There was the hideous cardigan with the cherries on it: which she wore often because it had been the last gift her father gave her. There was the fact that she overworked herself (particularly on friday nights) because she didn't want to go home to an empty flat; with no boyfriend or friends to keep her company. The cat, ultimately, had been a bad idea, as she was slightly allergic and it only made her feel like she was really doomed to be a spinster.

Sherlock often rolled his eyes when he thought about how ridiculously self-conscious Molly was about her marital status. To him, of course, relationships were trivial and more work than they were worth, but to people as sentimental as Molly it was all they lived for. Still, Molly was...fairly attractive. More than that however, she was clever and accomplished in her field and if she stopped dating or pursuing sociopaths (himself included; but thinking mostly of Moriarty) for all of two seconds, she could probably find some ordinary, dreadfully dull man to fulfill her expectations.

Her expectations, however, would have to wait a few more weeks.

Right at this moment, Sherlock needed her. Not in the same way he'd needed her when he was forced to play into Moriarty's tricks, but perhaps in another way that would give him just as much glee.

He needed Molly to teach Mary Morstan a lesson.

_Coffee? -SH_

He insisted for a second time. She had not responded to his text message the night before but he reasoned that it was late and given Molly's lack of social life, she was undoubtedly fast asleep by the time he'd texted.

_Busy. Can't leave the lab. Why don't you just stop by? -MH_

Sherlock huffed at the phone screen and sent a quick reply as the future Mrs. Watson strolled into the kitchen, wrapped in one of John's robes.

"You left your jar of fingers out on the table last night." She informed him as she took some milk from the refrigerator. "I put them in the fridge for you; don't want them going bad."

Sherlock smirked, still looking at his mobile's screen and wondered why on earth John couldn't be as understanding about his experiments as his fiancé was. He used to resent the nights she spent at Baker Street and consequently, the mornings where she invaded his routine and kitchen. At first, he'd purposely left severed heads and hands laying around in the hopes of discouraging the psychiatrist from overstaying her welcome (which as far as he was concerned, was non-existent) but to both his irritation _and _slight amusement, Mary took it in stride. Perhaps he had underestimated her squeamishness. She was a doctor, after all.

To his own shock, he found that she sometimes came in rather useful when Sherlock needed a differential or someone to bounce ideas off of during cases and John refused to help him. Mary was always up to the task.

"Who are you texting?" She smiled at him winningly as she settled into the chair opposite him and took a sip of her coffee.

"Doctor at St. Barts." He answered, not lying. "I need to go into the lab today."

"Ah." Sherlock raised an eyebrow and waited for her real response. "I thought perhaps you were asking someone out."

"Let it go, Mary." He said simply, with a roll of his eyes. He tucked his mobile into his coat pocket and focused on quickly scanning the newspaper, hoping for a good murder or perhaps a suspicious accident. He needed something to occupy him from what would no doubt be incessant fawning by Molly Hooper when she agreed to go to Mary and John's wedding with him. He briefly considered not asking her at all, but the thought of Mary's smug expression disappearing off her face for all of two seconds was enough to make Sherlock almost giddy to go to the hospital.

"Morning Sherlock."

Sherlock grunted a response to his colleague and John stopped in the middle of the kitchen, staring at Mary in confusion.

"I...thought you were going in to the hospital today?"

"No, I didn't schedule any sessions this week."

Once again, John furrowed his brow.

"But you were in the hospital these past few days."

"I was in the lab." She explained matter-of-factly and directed her stare at Sherlock. "Sherlock demanded I study a few brains for him and I certainly wasn't going to do it for free."

Sherlock gave just a small laugh as he continued to search the paper for his next case. Car crash: boring. It was an accident. Death in north London: Heart attack. Also boring.

"Hang on. You were helping Sherlock all week, all the while getting paid for being at the hospital but not taking patients." John shook his head a little, as if trying to understand. "Isn't that illegal?"

"What are they going to do," Mary quipped, raising a perfectly arched brow, "fire me?"

At that, even Sherlock had to concede that she was right. Although he hid his approving nod behind the newspaper. St. Bart's would struggle to find another psychiatrist as competent as Mary and so they were better off turning a blind eye to whatever she chose to do. Sherlock's relationship with Scotland Yard was not too different.

John however, was still baffled.

"This is..." he stopped at a loss for words and turned to Sherlock for support or a supply of adjectives; he found neither. Sherlock almost found it amusing that John still had the decency to be shocked by things after everything he himself had put him through. "Unbelievable. I'm marrying a female version of Sherlock!"

"Don't flatter her, John." Was Sherlock's quick response from behind the paper.

John simply made unintelligible, shocked sounds and walked out of the kitchen, mumbling something about a shower.

"It is a nice feeling to know that I still have the ability to shock him." Mary sounded rather content with herself.

_Be there in 30 mins. -SH_

Sherlock looked up from the text he'd just sent.

"John may be the only one."

"Am I that boring to you, Sherlock?"

He stood from the table and sent Mary a mocking smile.

"You're predictable. If you ever managed to surprise me, I'd probably die of the shock."

He began to walk out of the flat but could hear Mary's tinkling laugh behind him.

"You're on Mr. Holmes. But do remember that you don't have that many lives left."

* * *

Molly Hooper had long ago given up hope that Sherlock Holmes would ever be romantically interested in her. In fact, in her opinion, she'd spent far too many years pining over him; changing her hairstyle and lipstick in the hopes of attracting him only to end up with nothing.

Well; that wasn't entirely true. She didn't have _nothing. _She had a flat full of his things that he'd yet to collect from over a year ago when he came back from the dead and a shaky, awkward relationship with John Watson, who still hadn't entirely forgiven her for keeping Sherlock's survival a secret from him.

She also had a week's worth of suspension when the truth was uncovered and Stamford had to reluctantly suspend her for faking laboratory results. Not that it was the first time she ever did such a thing (unsurprisingly, always on Sherlock's demand) but with Sherlock's return being of such high profile, it would look very odd and insubordinate if the pathologist who lied to the authorities, faked a death and hid a man in her flat for three years -routinely stealing samples to supply for said man's experiments- didn't get _some _sort of punishment. Stamford had gone easy on her, really. She fully expected to lose her license had the man not had a soft spot for Sherlock.

After the initial shock of Sherlock's message wore off, Molly had come to her senses and realized that if there was any reason at all why Sherlock could possible be asking her to have coffee with him, it was because he needed something. And she would undoubtedly give it to him.

She'd gotten a lot better with her crush on Sherlock over the years. She was dating again and she only _sometimes_ checked him out when he wore that damned purple shirt. Still, she couldn't actually deny him anything he might need from her in the lab or the morgue. She supposed she was legally obligated.

It had been only a few weeks after Sherlock had gone public again, that Molly had endured a car ride from hell next to an expensively dressed brunette woman who was basically glued to her mobile, while Molly panicked thinking she was surely going to die at the hands of one of Moriarty's associates.

It turned out, much to her relief, to only be Mycroft Holmes; who had just as much love for the theatrics as his younger brother and also the means to perform them. He was very intimidating in requesting Sherlock have free reign at St. Bart's, yes, but hardly the life threatening situation Molly was imagining was in store for her. She agreed to give Sherlock all-access at the hospital. She even refused to take Mycroft's money. After all, she'd been catering to Sherlock's mad whims for years now; and for free.

* * *

"You've recently bought a dress." He said as he placed a cup of coffee at her desk. Molly almost asked how he knew but she knew better than that. Sherlock knew _everything. _"Is it for the wedding?"

She shrugged her shoulders and went back to her paperwork. She really was swamped today and it would be a lot easier if the consulting detective simply told her what outrageous thing he needed this time so she could get back to work.

"I haven't decided yet...If I'm going that is."

"Why wouldn't you go?" He seemed genuinely confused for a second and Molly only sighed.

"John still seems a bit...upset, about what happened. About me not telling him."

Sherlock scoffed. "Oh please, I can assure you, he's over it."

"I don't know. It might be a bit awkward."

"Nonsense. Besides, I need you to go. With me."

Molly nearly choked on her coffee.

"What?"

"Well you're obviously not going with anyone. You haven't had a whiff of a date in months. I need you to go with me. Face it Molly, it's the best offer you'll get."

She stood for a few shocked moments and stared at the tall man looming over her desk. She'd always imagined that if he ever did ask her out, it would be in a strange, very Sherlock-esque way, but outright rude and insulting never occurred to her. It really should have.

"No."

"No? What do you mean 'no'?" He looked taken a back and Molly almost smiled.

"I mean 'no'. I told you I may not even go to the wedding at all and I...don't want to...go with...you.." She finished the sentence hesitantly because although she knew Sherlock's emotions didn't work quite like others', she didn't want to hurt or insult him.

Sherlock however didn't look either hurt or insulted. Instead he narrowed his eyes at her and tilted his head.

"She spoke to you, didn't she?"

"What are you talking about?"

Sherlock rolled his eyes in annoyance but perhaps not at her.

"Never mind. Enjoy your coffee."

Sherlock whirled around and left the lab as quickly and dramatically as he'd entered it; a billowing of dark coat and blue scarf behind him and leaving Molly completely unsure of what had just happened.


End file.
